Final answer:
The kidneys are responsible for filtering the bloodstream to remove wastes and excess water, playing a crucial role in homeostasis.
Step-by-step explanation:
The organ that filters the bloodstream to remove harmful waste products and maintain balance is the kidneys. These bean-shaped structures perform many vital functions, including removing metabolic waste products from the bloodstream, managing the body's water balance, and maintaining the pH levels of the body's fluids. The blood filtration process done by the kidneys is critical, as all the blood in the human body is filtered many times a day - with about one and a half quarts per minute being circulated through them. The waste chemicals and excess water filtered by the kidneys are then expelled from the body as urine, a key aspect of homeostasis.